/* eslint-disable */
import XLSX from 'xlsx'

function auto_width(ws, data) {
	/*set worksheet max width per col*/
	const colWidth = data.map(row =>
		row.map(val => {
			/*if null/undefined*/
			if (val == null) {
				return { wch: 10 }
			} else if (val.toString().charCodeAt(0) > 255) {
				/*if chinese*/
				return { wch: val.toString().length * 2 }
			} else {
				return { wch: val.toString().length }
			}
		}),
	)
	/*start in the first row*/
	let result = colWidth[0]
	for (let i = 1; i < colWidth.length; i++) {
		for (let j = 0; j < colWidth[i].length; j++) {
			if (result[j]['wch'] < colWidth[i][j]['wch']) {
				result[j]['wch'] = colWidth[i][j]['wch']
			}
		}
	}
	ws['!cols'] = result
}

function json_to_array(key, jsonData) {
	return jsonData.map(v =>
		key.map(j => {
			return v[j]
		}),
	)
}

// fix data,return string
function fixdata(data) {
	let o = ''
	let l = 0
	const w = 10240
	for (; l < data.byteLength / w; ++l)
		o += String.fromCharCode.apply(null, new Uint8Array(data.slice(l * w, l * w + w)))
	o += String.fromCharCode.apply(null, new Uint8Array(data.slice(l * w)))
	return o
}

// get head from excel file,return array
function get_header_row(sheet) {
	const headers = []
	const range = XLSX.utils.decode_range(sheet['!ref'])
	let C
	const R = range.s.r /* start in the first row */
	for (C = range.s.c; C <= range.e.c; ++C) {
		/* walk every column in the range */
		var cell = sheet[XLSX.utils.encode_cell({ c: C, r: R })] /* find the cell in the first row */
		var hdr = 'UNKNOWN ' + C // <-- replace with your desired default
		if (cell && cell.t) hdr = XLSX.utils.format_cell(cell)
		headers.push(hdr)
	}
	return headers
}

export const export_table_to_excel = (id, filename) => {
	const table = document.getElementById(id)
	const wb = XLSX.utils.table_to_book(table)
	XLSX.writeFile(wb, filename)

	/* the second way */
	// const table = document.getElementById(id);
	// const wb = XLSX.utils.book_new();
	// const ws = XLSX.utils.table_to_sheet(table);
	// XLSX.utils.book_append_sheet(wb, ws, filename);
	// XLSX.writeFile(wb, filename);
}

export const export_json_to_excel = ({ data, key, title, filename, autoWidth }) => {
	const wb = XLSX.utils.book_new()
	data.unshift(title)
	const ws = XLSX.utils.json_to_sheet(data, { header: key, skipHeader: true })
	if (autoWidth) {
		const arr = json_to_array(key, data)
		auto_width(ws, arr)
	}
	XLSX.utils.book_append_sheet(wb, ws, filename)
	XLSX.writeFile(wb, filename + '.xlsx')
}

export const export_array_to_excel = ({ key, data, title, filename, autoWidth }) => {
	const wb = XLSX.utils.book_new()
	const arr = json_to_array(key, data)
	arr.unshift(title)
	const ws = XLSX.utils.aoa_to_sheet(arr)
	if (autoWidth) {
		auto_width(ws, arr)
	}
	XLSX.utils.book_append_sheet(wb, ws, filename)
	XLSX.writeFile(wb, filename + '.xlsx')
}

export const read = (data, type) => {
	/* if type == 'base64' must fix data first */
	// const fixedData = fixdata(data)
	// const workbook = XLSX.read(btoa(fixedData), { type: 'base64' })
	const workbook = XLSX.read(data, { type: type })
	const firstSheetName = workbook.SheetNames[0]
	const worksheet = workbook.Sheets[firstSheetName]
	const header = get_header_row(worksheet)
	const results = XLSX.utils.sheet_to_json(worksheet)
	return { header, results }
}

export default {
	export_table_to_excel,
	export_array_to_excel,
	export_json_to_excel,
	read,
}
